1. Field of the Invention
The present invention relates to a socket for an electrical part, such as semiconductor device (called “IC package” hereinlater), disposed between the electrical part and a printed circuit board so as to establish an electrical connection therebetween.
2. Related Art
One example of a known socket of this type is shown in FIG. 13, which is for example, disclosed in the Japanese Laid-open Patent Publication No. 2000-82554.
Referring to FIG. 13, a socket has a socket body 1 formed with a recessed portion 1a into which a contact pin 2 is accommodated. A printed circuit board 3 is disposed below the socket body 1 so as to arrange an IC package as electrical part, not shown in FIG. 13, on the upper side of the socket body 1.
The contact pin 2 is provided with a first contact portion 2a as a lower portion in the illustration, a second contact portion 2b as an upper portion in the illustration and an approximately U-shaped intermediate portion 2c having elastic or springy property. This U-shaped intermediate portion 2c is positioned between the first and second contact portions 2a and 2b so as to connect these portions 2a, 2b, 2c. 
The first contact portion 2a contacts the printed circuit board 3 and the second contact portion 2b, on the other hand, contacts a terminal of the IC package to thereby establish an electrical connection between the printed circuit board 3 and the IC package terminal through the contact pin 2.
According to such electrical connection, a performance test of the IC package is carried out by using an IC package test machine, and in accordance with this test result, it is discriminated whether the IC package is defective or not as a product.
In the known structure mentioned above, however, the U-shaped elastic portion 2c of the contact pin 2 urges both the contact portions 2a and 2b to ensure the contacting pressure between the printed circuit board 3 and the IC package terminal. Accordingly, in order to ensure displacement of both the contact portions 2a and 2b, it is obliged for the U-shaped portion to have a relatively long length, as an electric path, which may results in an adverse result of a high frequency IC package performance test.